Use of chiral 2-(phosphonomethoxy)propyl guanines as antiviral agents

ABSTRACT

The present invention provides chiral nucleotide analogs having the Formulas I and II ##STR1## and pharmaceutically acceptable salts and solvates thereof, and their pharmaceutical compositions for use in the treatment of viral infections, especially those caused by human immunodeficiency virus (HIV).

This application is related to copending U.S. Ser. No. 08/028,733, whichis a continuation of copending application U.S. Ser. No. 07/801,338,filed Dec. 2, 1991, now abandoned, which is a continuation of Ser. No.07/650,531, filed Feb. 5, 1991, now abandoned, which is a continuationof Ser. No. 07/513,307, filed Apr. 20, 1990, now abandoned.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to certain chiral nucleotide analogs andtheir compositions and use in the treatment of viral infections. Inparticular, the present invention relates to certain chiral acyclictreatment of human immunodeficiency virus (HIV) diseases.

2. Information Disclosure Statement

Infectious viral diseases are recognized as an important medicalproblem. Progress against infectious viral diseases requires thedevelopment of drugs with selective antiviral activity while remainingbenign to normal cell lines. A number of antiviral agents currentlyunder study, which seem to possess some selectivity, are nucleosideanalogs. In general, these compounds are structural analogs of thenaturally occurring nucleosides. Structural modification in either thepurine or pyrimidine base nucleus and/or the saccharide componentresults in a synthetically modified nucleoside derivative which, whenincorporated into a viral nucleic acid forming process, acts to disruptfurther synthesis of viral nucleic acid. Effectiveness of theseantiviral agents depends on selective conversion by viral enzymes, butnot by host enzymes, to the corresponding nucleotide analog which isthen converted to the triphosphate and incorporated into viral nucleicacid. A problem with this antiviral strategy has been the emergence ofcertain viral strains whose enzymes poorly promote phosphorylation ofthe nucleoside analogs. To circumvent this problem, intact nucleotideanalogs appear to be potentially quite useful as antivirals forincorporation into viral nucleic acid.

Reist and Sturm in PCT/U.S. 84/00737, published Dec. 6, 1984, disclosednew phosphonic acid analogs of nucleoside phosphates which are useful asantivirals for incorporation into viral DNA. The structural formula forthese compounds is shown below as Formula 1. ##STR2##

In the Reist compounds, B is a purine or pyrimidine base: R₁ and R₂together complete a β-pentofuranose sugar or R₁ is H and R₂ is H orhydroxymethyl; R₃ is H or OH; X is H, OH, or together with Y is carbonyloxygen, and Y can also be H; Z₁ and Z₂ are H or alkyl. These artcompounds are generally distinguished from the compounds of the instantinvention by (a) the ether-oxygen link to the carbon atom attached tothe base which is intended to preserve or mimic the acetal oxygen bondof a pentofuranose sugar ring and (b) the phosphate modification whichis a phosphonoalkylene moiety. In contrast, the acyclic sugar analogcomponent of the instant compounds is comprised of an all carbon atombackbone up to a phosphonomethoxy moiety.

Similarly, synthesis and anti-Herpes virus activity of phosphate andphosphonate derivatives of 9-[(1,3-dihydroxy-2-propoxy)methyl]guanine(Formula 2) were disclosed by Prisbe, et al., in J. Med. Chem., 1986,29, 671. ##STR3##

More closely related are adenine phosphonic acid analogs (Formula 3) andtheir syntheses which were disclosed in the United Kingdom patentapplication of Holy, et al.. GB 2,134,907A, published on August 22,1984, and its related U.S. Pat. No. 4,659,825. ##STR4##

In Formula 3, R₂ and R₃ may be hydrogen and R₄ is independently ahydrogen atom or a --CH₂ P(O)(OH)₂ group.

A preferred example of one of these compounds, known as (S)-HPMPA(Formula 4), was disclosed by E. DeClercq, et al., in Nature, 1986, 323,pp. 464-467, and in Antiviral Research, 1987, 8, pp. 261-272, andearlier by A. Holy, et al., Nucleic Acids Research, Symposium Series No.14, 1984, pp. 277-278. The reported antiviral activity of HPMPA residesonly in the isomer having the (S)-configuration at the chiral center onthe side chain. The corresponding (R)-isomer is reported to be devoid ofantiviral activity. ##STR5##

European Patent Application EP-253,412 of A. Holy, et al., published onJan. 20, 1988, discloses a series of N-phosphonylmethoxyalkylderivatives of pyrimidine and purine bases (Formula 5) exhibitingantiviral activity ##STR6## in which R is a hydrogen atom or ahydroxymethyl group and B is an optionally substituted pyrimidin-1-yl,pyrimidin-3-yl, purin-3-yl, purin-7-yl, or purin-9-yl residue, wherebyunsubstituted adenin-9-yl is excluded. Substituent B is preferably,inter alia, guanin-9-yl. One of the examples wherein B is guanin-9-yland R is --CH₂ OH (HPMPG) is disclosed only as the racemic (RS)-isomer.

European Patent Application EP-269,947 of R. R. Webb, II, et al.,published on Jun. 8, 1988, discloses a series of phosphonomethoxyalkenepurine and pyrimidine derivatives which are useful as antiviral agentsand have the general Formula 6 ##STR7## wherein B is a purine orpyrimidine base; alk₁, alk₂, and alk₃ are chemical bonds or alkylenegroups; Q is hydrogen or hydroxy; and R₁ -R₄ are hydrogen or alkyl,provided that B is not 9-adenyl when R₁ -R₄ is hydrogen and alk₁, alk₂,alk₃, and Q are as disclosed by A. Holy, et al., GB 2,134,907, citedabove. There is also generically disclosed in European PatentApplication EP-269,947 as Example 32 and Example 35 in Table 1 and inclaim 8 the racemic compound of the present invention. The racemiccompound of the present invention was never made and was suggested asonly one of many possible combinations.

In Nucleotide Analogs as Antiviral Agents; ACS Symposium Series 401;Martin, J. C. Ed.: Washington, D.C., 1989, Chapter 5, pp. 72-87; J. J.Bronson, et al., report on the series of nucleotide analogs disclosed inthe above cited European Patent Application EP-269,947 publication.Also, in J. Med. Chem., 1990, 33, 1207-1213, C. U. Kim, et al.,describes a similar series of compounds.

The present applicants have separately prepared the (R)- and (S)-isomersof 9-[2-(phosphonomethoxy)propyl]guanine (2'-methyl-PMEG) and havediscovered, surprisingly, that both are active against humanimmunodeficiency virus (HIV). In sharp contrast, as disclosed in thepresent invention, both the (R)- and (S)-isomers of HPMPG are inactiveagainst HIV. More surprising was the unexpected finding that the(R)-isomer of 2'-methyl-PMEG provides complete protection of both MT4and CEM-SS cells against HIV over a concentration range of from about 5to 100 μM with no observable cytotoxicity at concentrations less than100 μM. In contrast, PMEG is approximately 30 fold more cytotoxic than(R)-2'-methyl-PMEG.

There is no teaching contained in these references, or combinationthereof, which would make obvious the use of the instant compoundsagainst HIV infections. Furthermore, there is no teaching which wouldsuggest the preparation of one specific isomer and that one isomer wouldprovide both unexpected lower toxicity and greater selectivity as ananti-HIV agent.

SUMMARY OF THE INVENTION

The present invention relates to the selective preparation of the (R)-and (S)-isomers of 9-[2-(phosphonomethoxy)propyl]guanine, which are alsodesignated herein as 2'-methyl-PMEG. These compounds differ from thenatural nucleotides by having structural variations in their sugaranalog component and in the nature of the oxygen-carbon-phosphorousbonds. The compounds of this invention are represented by structuralFormulas I and II. ##STR8##

The present invention also relates to the treatment of viral infectionsin mammals, including humans, and, in particular, those caused by humanimmunodeficiency virus (HIV) with a therapeutically-effective amount ofa compound of Formulas I or II, and pharmaceutically acceptable saltsthereof. This invention further relates to the formulation of thesecompounds into pharmaceutical compositions and the use of thesecompositions to treat viral infections.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates the relative effects between cellular toxicity ofuninfected and anti-HIV activity of infected MT4 cells by increasingconcentrations of (R)-2'-methyl-PMEG (Compound I).

FIG. 2 illustrates the relative effects between cellular toxicity ofuninfected and anti-HIV activity of infected MT4 cells by increasingconcentrations of PMEG.

FIG. 3 illustrates the relative effects between cellular toxicity ofuninfected and anti-HIV activity of infected CEM-SS cells by increasingconcentrations of (R)-2'-methyl-PMEG (Compound I).

FIG. 4 illustrates the relative effects between cellular toxicity ofuninfected and anti-HIV activity of infected CEM-SS cells by increasingconcentrations of PMEG.

FIG. 5 illustrates the relative effects between cellular toxicity ofuninfected and anti-HIV activity of infected CEM-SS cells by increasingconcentrations of (S)-2'-methyl-PMEG (Compound II).

FIG. 6 illustrates the relative effects between cellular toxicity ofuninfected and anti-HIV activity of infected CEM-SS cells by increasingconcentrations of (R)-HPMPG.

FIG. 7 illustrates the relative effects between cellular toxicity ofuninfected and anti-HIV activity of infected CEM-SS cells by increasingconcentrations of (S)-HPMPG.

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to the stereospecific synthesis of boththe (R) and (S) chiral isomers of compounds of Formulas I and II,respectively, and to pharmaceutically acceptable salts thereof. ##STR9##

The compounds of the present invention also exhibit antiviral activitywithout observable cytotoxicity and, thus, can advantageously be used inthe treatment of viral infections. In particular, these compounds areeffective against human immunodeficiency virus (HIV). The most preferredcompound of the present invention is the chiral (R)-isomer of Formula Iwhich, surprisingly, exhibits complete cell protection against HIV overa broad concentration range with no observable cytotoxicity.

The present invention, as indicated, also pertains to thepharmaceutically acceptable non-toxic salts of the compounds of FormulasI and II. Such physiologically acceptable salts may include thosederived by combination of appropriate cations such as alkali andalkaline earth metal ions or ammonium and quaternary amino ions with theacid anion moiety of the phosphonic acid group. Additionally, salts maybe formed from acid addition of certain organic and inorganic acids withbasic centers of the purine, specifically guanine, base. Finally, it isto be understood that the compounds of the present invention can existin various tautomeric forms, in their unionized as well as zwitterionicform and/or in the form of solvates, which are all considered to beincluded within the scope of the present invention

The compounds of Formulas I and II can be prepared by a sterospecificsynthesis following the general procedures illustrated in ReactionSchemes 1 and 2, respectively The procedures for the preparation ofcompounds of Formulas I and II are similar, except for the use ofopposite enantiomeric (chiral) starting materials of Formulas IIIa andIIIb. ##STR10##

The preparation of the chiral (R)-isomer of Formula I is illustrated inReaction Scheme 1 starting with the completely protected phosphonateester of Formula IIIa which is prepared from chiral(S)-2,3-O-isopropylidene glycerol following the procedure described byJ. J. Bronson, et al., in J. Med. Chem., 1989, 32. 1457, except that thephosphonate is protected with an isopropyl instead of an ethyl group. Incontrast to the previous use of starting material of Formula IIIa,wherein the mesylate group is utilized as a leaving group, in thisinstance, the mesylate is converted to the iodo compound of Formula IVawith sodium iodide in an inert organic solvent such as acetonitrile,acetone, and the like at the reflux temperature of the solvent. Thedesired methyl substituent of the compound of Formula Va having thedesired stereochemical configuration is advantageously produced from theiodo compound of Formula IVa by catalytic hydrogenation using, forexample, palladium on carbon. The benzyl protecting group of thecompound of Formula Va is then selectively removed by catalytichydrogenolysis using palladium hydroxide on carbon in an organic mediumcontaining cyclohexene. The resulting primary alcohol of Formula VIa isthen converted to an organic leaving group such as halide, tosylate,mesylate, and triflate in the presence of an organic base.Advantageously, the reaction is carried out with methylsulfonyl chlorideand triethylamine to give the mesylate of Formula VIIa. The alkylationof 2-amino-6-chloropurine is carried out in a coupling reaction with themesylate of Formula VIIa in an inert organic solvent such asacetonitrile, dimethylformamide, and the like in the presence of anexcess of inorganic bases such as cesium carbonate or sodium hydride.The completely protected phosphonate ester of Formula VIIIa is firsttreated with bromotrimethylsilane and then the intermediate ishydrolyzed in an acidic medium, for example, 2N hydrochloric acid, toproduce the optically active (R)-isomer of Formula I. ##STR11##

The preparation of the chiral (S)-isomer of Formula II is illustrated inReaction Scheme 2 starting with the completely protected phosphonateester of Formula IIIb which is prepared from chiral(R)-2,3-O-isopropylidene glycerol following the procedure described byJ. J. Bronson, et al., in J. Med. Chem., 1989, 32, 1457, except that thephosphonate is protected with an isopropyl instead of an ethyl group.The optically active (S)-isomer of Formula II is prepared from thephosphonate ester of Formula IIIb as shown in Reaction Scheme 2following the same general procedures and reaction sequences asillustrated in Reaction Scheme 1 for the preparation of the (R)-isomerof Formula I. ##STR12##

In an alternate procedure for the preparation of the (R)-isomer ofFormula I, the chiral intermediate of Formula VIa may be preparedstarting with (S)-1,2-propanediol of Formula IX, as illustrated inReaction Scheme 3. The primary alcohol of the compound of Formula IX canselectively be protected with p-anisylchlorodiphenylmethane (MMt-Cl) inthe presence of dimethylaminopyridine and triethylamine to produce thecompound of Formula X. The secondary alcohol of Formula X is thenalkylated with diisopropyl tosyloxymethanephosphonate to give theintermediate of Formula XI which is then hydrolyzed with acid to producethe chiral intermediate of Formula VIa.

In view of the unexpected biological activity observed with thecompounds of the present invention, applicants wished to compare the HIVactivity of the instant compounds with the activity of the preferredcompounds described in European Patent Application EP-269,947 and thesimilarly disclosed compound of European Patent Application EP-253,412.Previous reports have indicated that the antiviral activity ofnucleoside and nucleotide analogs may reside in only one of the isomerswhich contain a chiral center. However, European Patent ApplicationEP-253,412 discloses the preparation of the racemic (RS) mixture whileEuropean Patent Application EP-269,947 discloses the preparation of the(S)-isomer of the compounds the present applicants wished to compare.Accordingly, it was necessary for the present applicants to prepare the(R)- and (S)-isomers of 9-[3-hydroxy-2-(phosphonomethyl)propyl]guanine,also designated as HPMPG, in order for a direct comparison to be made.Reaction Schemes 4 and 5 illustrate the stereospecific synthesis whichwas used to prepare the (R)-isomer and (S)-isomer of HPMPG,respectively. ##STR13##

The compound of Formula XIV [(R)-HPMPG] may be prepared from thecompound of Formula IIIa, as illustrated in Reaction Scheme 4. Thus, theintermediate of Formula IIIa is treated with 6-O-benzylquanine in thepresence of an inorganic base such as cesium carbonate in an inertorganic solvent to produce the coupled alkylated product of FormulaXIIa. Subsequent removal of the benzyl protecting groups was carried outby catalystic hydrogenolysis using palladium hydroxide on carbon in thepresence of cyclohexene to produce the intermediate of Formula XIIIa.The phosphonate ester of Formula XIIIa is treated withtrimethylsilylbromide to produce the optically active (R)-HPMPG ofFormula XIV. ##STR14##

The compound of Formula XV [(S)-HPMPG] may be prepared from the compoundof Formula IIIb, as illustrated in Reaction Scheme 5. The startingmaterial of Formula IIIb is coupled with 6-O-benzylguanine to give theintermediate of Formula XIIb and then removal of the benzyl groupsfollowed by hydrolysis of the phosphonate ester of Formula XIIIb,similar to the procedures used in Reaction Scheme 4, to produce theoptically active (S)-HPMPG of Formula XV.

Pharmaceutically acceptable salts of a Formula I or II compound of thisinvention are prepared by methods known in the art. The salts includeammonium salts and salts of physiologically acceptable metals,particularly Li⁺, K⁺, Na⁺, Ca⁺⁺, Mg⁺⁺, and comprise a further aspect ofthe invention. Metal salts can be prepared by reacting the metalhydroxide with a Formula 1 or II compound of this invention. Examples ofmetal salts which can be prepared in this way are salts containing Li⁺,Na⁺, and K⁺. A less soluble metal salt can be precipitated from thesolution of a more soluble salt by addition of the suitable metalcompound. Acid salts may be prepared by reacting a Formula I or IIcompound of the invention with an inorganic or organic acid, e.g., HCl,HBr, H₂ SO₄, organic sulfonic acids, and the like.

ABBREVIATIONS OF COMPOUNDS

The abbreviations used to identify the compounds of this nucleotideclass are well-known in the art and are used herein as defined below.

    ______________________________________                                        PMEG:         9-[2-(phosphonomethoxy)ethyl]-                                                guanine (compound of Example 7 in                                             European Patent Application                                                   EP-269,947 and compound 5 in                                                  TABLE 2 of European Patent                                                    Application EP-253,412)                                         (R)-2'-methyl-PMEG:                                                                         (R)-9-[2-(phosphonomethoxy)pro-                                               pyl]guanine (compound of Example                                              7)                                                              (S)-2'-methyl-PMEG:                                                                         (S)-9-[2-(phosphonomethoxy)pro-                                               pyl]guanine (compound of Example                                              13)                                                             (R)-HPMPG:    (R)-9-[3-hydroxy-2-(phosphono-                                                methoxy)propyl]guanine (compound                                              of Example 16)                                                  (S)-HPMPG:    (S)-9-[3-hydroxy-2-(phosphono-                                                methoxy)propyl]guanine (compound                                              of Example 19)                                                  ______________________________________                                    

BIOLOGICAL ACTIVITY

To illustrate the antiviral activity against both herpes viruses and, inparticular, human immunodeficiency virus (HIV), the compounds of theinstant invention and a representative number of known compounds arepresented in Tables I and II and FIGS. 1-7, along with their relativecytotoxicities.

In Vitro Antiviral Activity

The compounds were evaluated for antiviral activity in vitro by thestandard plaque reduction assay. Experiments were conducted with verocells (African Green Monkey Kidney cells) infected with herpes simplexvirus Type 1 (HSV-1) [BW^(s) strain, C. D. Sibrack, et al., Infect.Dis., 1982, 146, 673] and herpes simplex virus Type 2 (HSV-2) [G strain,obtained from American Tissue Culture Collection, Rockville, Md.] andwith MRC-5 cells (human embryonic lung (diploid) cells) infected withhuman cytomegalovirus (HCMV) [AD169 strain, obtained from AmericanTissue Culture Collection, Rockville, Md.].

Briefly, confluent cell monolayers in 24-well plates were infected with30-50 plaque-forming units of virus in 100 μl of phosphate-bufferedsaline. After a 1 hour adsorption period, residual inoculum was replacedwith 1 mL of the appropriate dilution of the test compound which hadbeen freshly prepared in Eagle's minimal essential medium (EMEM)containing 10% fetal bovine serum. After a 48 hour incubation period at37° C. in a 5% CO₂ atmosphere, cell monolayers were fixed and stainedwith Carbol fuchsin and plaques were counted. The antiviral potency ofthe compound was determined by IC₅₀, the inhibitory concentrationnecessary to reduce the number of plaques by 50% of those in the viruscontrol cultures. The antiviral activities of the test compounds againstHSV-1, HSV-2, and HCMV are shown in Table 1.

                  TABLE 1                                                         ______________________________________                                                     IC.sub.50 (μg/mL)                                             Compound       HSV-1.sup.a                                                                             HSV-2.sup.a                                                                             HCMV.sup.b                                 ______________________________________                                        PMEG           0.09      0.31      <0.1                                       (R)-2'-methyl-PMEG                                                                           --        25        5.0                                        (S)-2'-methyl-PMEG                                                                           --        25        5.0                                        (R)-HPMPG      32        32        0.5                                        (S)-HPMPG      8         31        0.9                                        ______________________________________                                         .sup.a) In vero cells.                                                        .sup.b) In MRC5 cells.                                                   

ASSAYS WITH HUMAN IMMUNODEFICIENCY VIRUS (HIV)

Compounds were evaluated for activity against human immunodeficiencyvirus (LAV_(BRU) strain obtained from Luc Montagnier, Institut Pasteur,Paris, France) in CEM-SS cells (P. L. Nara, et al., in AIDS Res. Human.Retroviruses, 1987, 3, 283-302) or in MT-4 cells (S. Harada, et al., inScience, 1985, 229, 563-566) using the XTT assay described by O. S.Weislow, et al., in J. Natl. Cancer Instit., 1989, 81, 577-586. CEM-SScells were obtained from Owen Weislow at the National Cancer Institute,and MT-4 cells were obtained from Doug Richman at the University ofCalifornia at San Diego. Cells were exposed to HIV and cultured inmicrotiter plates in the presence of test compounds at concentrations of0.0013, 0.0064, 0.032, 0.16, 0.8, 4, 20, 100, and 500 μM. On day 7post-infection, the antiviral effect was measured using the XTT assay inwhich an optical density (OD) reading is obtained at each drugconcentration. The optical density reading is proportional to the numberof viable cells. Plots of drug concentration versus optical densityreadings are shown in FIGS. 1-7. Assays run in infected cells show theantiviral effect of the test compounds, where an increase in the numberof viable cells (higher OD reading) reflects the protective, antiviralactivity of the compound. Assays run in uninfected cells provide ameasure of cellular toxicity.

The antiviral effect is also expressed (see Table 2) as theconcentration of compound which increases the number of viable cells ininfected cultures to 50%, that of the untreated, uninfected controlcultures (ED₅₀) The cellular toxicity is expressed as the concentrationof compound which reduces the number of viable cells to 50%, that of theuntreated control (TD₅₀). The selectivity index (SI) is the ratio ofTD₅₀ to ED₅₀.

The anti-HIV activity and cellular toxicity of the test compounds areplotted in FIGS. 1-7 as a function of optical density verus increasinglog concentrations of the test compounds (XTT assay). FIGS. 1-7 visuallyshow the results of the relative anti-HIV activity of the test compoundson infected cells (- ) against the cellular toxicity of the same testcompound on uninfected cells (□-□).

The anti-HIV activity of the (R)-isomer (R)-2'-methyl-PMEG of theinstant invention is shown in FIG. 1 (MT4 cells) and FIG. 3 (CEM-SScells) while the (S)-isomer (S)-2'-methyl-PMEG is shown in FIG. 5(CEM-SS cells). The anti-HIV activity of the comparison compound PMEG isshown in FIG. 2 (MT4 cells) and FIG. 4 (CEM-SS cells) while the resultsof the anti-HIV assay of the (R)- and (S)-HPMPG are shown in FIGS. 6 and7 (CEM-SS cells), respectively.

FIGS. 1 and 3 show that, over a concentration range of 5 to 100 μM,(R)-2'-methyl-PMEG provides complete protection from the humanimmunodeficiency virus in both MT4 and CEM-SS cell lines with noobserved cellular toxicity at concentrations less than 100 μM. FIG. 5shows that (S)-2'-methyl-PMEG provides complete protection from HIV inCEM-SS cells at 100 μM with no observed cellular toxicity atconcentrations less than 100 μM. By comparison, as shown in FIG. 2, PMEGis highly toxic to MT4 cells at concentrations above 0.1 μM, and noanti-HIV effect can be measured due to the cellular toxicity of PMEG.Although PMEG does exhibit some anti-HIV effect in CEM-SS cells, thecellular toxicity of PMEG once again prevents protection from the virus.Furthermore, by comparison, both (R)- and (S)-HPMPG are clearly inactiveagainst HIV in CEM-SS cells as shown in FIGS. 6 and 7, respectively.

Selectivity Index of Test Compounds

Another estimate of the effectiveness of a compound for use against HIVin the prevention and/or treatment of AIDS is a selectivity index (an invitro "therapeutic index"), the ratio of the effective dose to the toxicdose. The selectivity index (SI) for (R)- and (S)-2'-methyl-PMEG of theinstant invention and for the comparison compounds PMEG and (R)- and(S)-HPMPG are shown in Table 2. The data in Table 2 clearly shows that(R)-2'-methyl-PMEG is both a potent and selective anti-HIV agent ascompared to the other compounds having a selectivity index greater than500.

                  TABLE 2                                                         ______________________________________                                        Anti-HIV Data for PMEG, ( .sub.-- R)- and ( .sub.-- S)-2'-methyl-PMEG,        and                                                                           (R)- and (S)-HPMPG in CEM-SS Cells Evaluated by XTT Assay                     Compound     ED.sub.50 (μM).sup.a                                                                  TC.sub.50 (μM).sup.b                                                                   SI.sup.c                                  ______________________________________                                        PMEG         0.2        15          30                                        ( .sub.-- R)-2'-methyl-PMEG                                                                1          >500        >500                                      ( .sub.-- S)-2'-methyl-PMEG                                                                12         300         25                                        ( .sub.-- R)-HPMPG                                                                         500        >500        >1                                        ( .sub.-- S)-HPMPG                                                                         NA.sup.d   350         --                                        ______________________________________                                         .sup.a) Effective Dose 50: In infected cells, concentration of compound       which results in an increase in the number of viable cells to 50% that of     uninfected control.                                                           .sup.b) Toxic Dose 50: In uninfected cells, concentration of compound         which results in a 50% decrease of viable cells.                              .sup.c) Selectivity Index: Ratio of TD.sub.50 to ED.sub.50.                   .sup.d) NA: Not active at concentrations up to 500 μM.                

The invention, accordingly, provides compounds of Formulas I and II andtheir pharmaceutically acceptable salts and solvates thereof and,preferably, the compound of Formula I which is substantially free of the(S)-isomer and its pharmaceutically acceptable salts and solvatesthereof for use in the therapy or prophylaxis of viral infections,especially human immunodeficiency virus, in a human subject.

The compounds of this invention, including the pharmaceuticallyacceptable salts and solvates thereof, have desirable antiviralactivity. They exhibit activity against DNA viruses and retroviruses. Inparticular, the compound of Formula I exerts a significant anti-HIVeffect with no observed cytotoxicity.

For use against viral infections, the compounds of this invention may beformulated into pharmaceutical preparations in any convenient way, andthe invention, therefore, also includes, within its scope,pharmaceutical compositions comprising a compound of Formulas I or II ora pharmaceutically acceptable salt or solvate thereof adapted for use inhuman medicine. Such compositions may be presented for use inconventional manner in admixture with one or more pharmaceuticallyacceptable carriers or excipients. The reference Remington'sPharmaceutical Sciences, 15th Edition, by E. W. Martin (Mark PublishingCompany, 1975), discloses typical carriers and methods of preparation.

For antiviral purposes, the compounds may be administered topically orsystemically. By systemic administration is intended oral, rectal, andparenteral (i.e., intramuscular, intravenous, subcutaneous, and nasal)routes. Generally, it will be found that, when a compound of the presentinvention is administered orally, a larger quantity of the reactiveagent is required to produce the same effect as the smaller quantitygiven parenterally. In accordance with good clinical practice, it ispreferred to administer the instant compounds at a concentration levelthat will produce effective antiviral without causing any harmful oruntoward side effects.

Therapeutically and prophylactically the instant compounds are given aspharmaceutical compositions comprised of an effective antiviral amountof a compound of Formulas I or II or a pharmaceutically acceptable saltthereof and a pharmaceutically acceptable carrier, as statedhereinabove. Pharmaceutical compositions for effecting such treatmentwill contain a major or minor amount, e.g., from 95% to 0.5% of at leastone compound of the present invention in combination with apharmaceutical carrier, the carrier comprising one or more solid,semi-solid, or liquid diluents, fillers, and formulation adjuvants whichare non-toxic, inert, and pharmaceutically acceptable. Suchpharmaceutical compositions are preferable in dosage unit form; i.e.,physically discreet units containing a predetermined amount of the drugcorresponding to a fraction or multiple of the dose which is calculatedto produce the desired therapeutic response. Other therapeutic agentscan also be present. Pharmaceutical compositions providing from about0.1 to 500 mg of the active ingredient per unit dose are preferred andare conventionally prepared as tablets, lozenges, capsules, powders,aqueous or oily suspensions, syrups, elixirs, and aqueous solutions.Preferred oral compositions are in the form of tablets or capsules andmay contain conventional excipients such as binding agents (e.g., syrup,acacia, gelatin, sorbitol, tragacanth, or polyvinylpyrrolidone), fillers(e.g., lactose, sugar, maize-starch, calcium phosphate, sorbitol, orglycine), lubricants (e.g., magnesium stearate, talc, polyethyleneglycol, or silica), disintegrants (e.g., starch), and wetting agents(e.g., sodium lauryl sulfate). Solutions or suspensions of a Formula Ior II compound with conventional pharmaceutical vehicles are employedfor parenteral compositions, such as an aqueous solution for intravenousinjection or an oily suspension for intramuscular injection. Suchcompositions having the desired clarity, stability, and adaptability forparenteral use are obtained by dissolving from 0.1% to 10% by weight ofthe active compound in water or a vehicle consisting of a polyhydricaliphatic alcohol, such as glycerine, propylene glycol, and polyethyleneglycol or mixtures thereof. The polyethylene glycols consist of amixture of non-volatile, usually liquid, polyethylene glycols which aresoluble in both water and organic liquids and have molecular weightsfrom about 200 to 1500.

Considering the biological activities possessed by the compounds of theinstant invention, it can be seen that these compounds have antiviralproperties particularly suited to their use in combating acquiredimmunodeficiency syndrome (AIDS). Thus, another aspect of the instantinvention concerns a method for treating HIV infections in mammals,including humans, in need of such treatment which comprises systemic ortopical administration to such mammal of an effective dose of a FormulaI or II compound or a pharmaceutically acceptable salt or solvatethereof. A further aspect of the instant invention concerns a method fortreating human cells infected with HIV infections which comprisessystemic or topical administration to such cells of an effective dose ofa Formula I or II compound or a pharmaceutically acceptable salt orsolvate thereof. On the basis of testing, an effective dose could beexpected to be from about 0.001 to about 30 mg/kg body weight. It isenvisioned that, for clinical antiviral application, compounds of theinstant invention will be administered in the same manner and use as forthe reference drugs AZT, DDI, and D4T. For clinical applications,however, the dosage and dosage regimen must, in each case, be carefullyadjusted, utilizing sound professional judgment by the physician andconsideration of the age, weight, and condition of the patient, theroute of administration, and the nature and gravity of the illness.Generally, a daily oral dose will comprise from about 0.1 to about 750mg, preferably 10-500 mg of a Formula I or II compound administered from1 to 3 times a day. In some instances, a sufficient therapeutic effectcan be obtained at lower doses while larger doses will be required inothers. It is also envisioned that a compound of Formula I or II may beadministered on a weekly schedule, such as once or twice per week; thedosage to be used in such a regimen may be adjusted with dueconsideration of factors listed above and to maintain serum drug levelat an anti-HIV effective level.

DESCRIPTION OF SPECIFIC EMBODIMENTS

In the following examples, all temperatures are given in degreesCentigrade. Melting points were recorded on an Electrothermal digitalcapillary melting point apparatus, and boiling points were measured atspecific pressures (mm Hg), and both temperatures are uncorrected.Proton magnetic resonance (¹ H NMR) spectra were recorded on a Bruker AM300, or Varian Gemini 300 spectrometer. All spectra were determined inCDCl₃, DMSO-d₆, or D₂ O unless otherwise indicated, and chemical shiftsare reported in 6 units downfield from the internal standardtetramethylsilane (TMS), and interproton coupling constants are reportedin Hertz (Hz). Splitting patterns are designated as follows: s, singlet;d, doublet, t, triplet; q, quartet; m, multiplet; br, broad peak; anddd, doublet of doublet. Carbon-13 nuclear magnetic resonance ¹³ C NMR)spectra were recorded on a Bruker AM 300 or Varian Gemini 300spectrometer and were broad band proton decoupled. All spectra weredetermined in CDCl₃, DMSO-d₆, or D₂ O unless otherwise indicated withinternal deuterium lock, and chemical shifts are reported in δ unitsdownfield from tetramethylsilane, relative to an internal standard.Infrared (IR) spectra were determined on a Perkin-Elmer 1800 FT-IRspectrometer from 4000 cm⁻¹ to 400 cm⁻¹, calibrated to 1601 cm⁻¹absorption of a polystyrene film, and are reported in reciprocalcentimeters (cm⁻¹). Optical rotations [α]_(D) ²⁰ were determined on aPerkin-Elmer 41 polarimeter in the solvents indicated. Ultravioletspectra were determined on a Hewlett Packard 8452 diode arrayspectrophotometer in the solvent and concentration indicated. Massspectra were recorded on a Kratos MS-50 or a Finnegan 4500 instrumentutilizing the fast atom bombardment (FAB) or direct chemical ionization(DCI) technique. The mass data are expressed in the format: protonatedparent ion (MH⁺).

Analytical thin-layer chromatography (TLC) was carried out on precoatedsilica gel plates (60F-254) and visualized using UV light, iodinevapors, and/or staining with one of the following reagents: (a)methanolic phosphomolybdic acid (2%) and heating; (b) reagent (a)followed by 2% cobalt sulphate in 5M H₂ SO₄ and heating. Columnchromatography, also referred to as flash column chromatography, wasperformed in a glass column using finely divided silica gel (32-63 μm onsilica gel-H) and pressures somewhat above atmospheric pressure with theindicated solvents. Reversed phase analytical thin-layer chromatographywas carried out on Analtech precoated reversed phase F (250 microns)plates and visualized using UV light or iodine vapors. Reversed phasecolumn chromatography was performed in a glass column using BakerOctadecyl (C₁₈), 40 μm.

All evaporations of solvents were performed under reduced pressure.Celite is a registered trademark of the Johns-Manville ProductsCorporation for diatomaceous earth. As used herein, the term hexanes isa mixture of isomeric C₆ hydrocarbons as specified by the AmericanChemical Society, and the term "inert" atmosphere is an argon ornitrogen atmosphere unless otherwise indicated.

EXAMPLE 1(R)-3-O-Benzyl-2-O-[(diisopropylphosphono)methyl]-1-O-(methanesulfonyl)glycerol

The title compound was prepared from (S)-2,3-O-isopropylidene glycerolfollowing the procedure described by J. J. Bronson, et al., in J. Med.Chem., 1989, 32, 1457.

¹ H NMR (CDCl₃, 300 MHz) δ 7.25-7.38 (m, 5 H, PhH), 4.63-4.77 (m, 2 H,2×POCH), 4.51 (s, 2 H, OCH₂ Ph), 4.39 (dd, J=3.6 , 11.2 Hz, 1 H, CH₂OMs), 4.29 (dd, J=5.7, 11.2 Hz, 1 H, CH₂ OMs), 3.90 (dd, J=8.8, 13.7 Hz,1 H, OCH₂ P), 3.84-3.91 (m, 1 H, 2-CH), 3.83 (dd, J=8.7, 13.7 Hz, 1 H,OCH₂ P), 3.61 (dd, J=5.0, 10.1 Hz, 1 H, CH₂ OBn), 3.56 (dd, J=5.5, 10.1Hz, 1 H, CH₂ OBn), 3.03 (s, 3 H, CH₃ SO₂), and 1.27-1.32 (m, 12 H,4×POCHCH₃).

¹³ C NMR (CDCl₃, 75 MHz) δ: 137.7, 128.7, 128.1, 127.9, 78.4 (d, ³J_(c),p =11 Hz, C-2), 73.5 (CH₂ Ph), 71.2 (t, ² J_(c),p =5 Hz, POCH),69.2 and 68.2 (CH₂ OBn and CH₂ OMs), 65.1 (d, ¹ J_(c),p =169 Hz, OCH₂P), 37.3 (CH₃ SO₂), 23.9 (d, ³ J_(c),p =5 Hz, POCHCH₃), and 23.8 (d, ³J_(c),p =4 Hz, POCHCH₃).

MS (methane, DCI) m/e: 439 (MH⁺).

Anal. Calcd. for C₁₈ H₃₁ O₈ PS: C, 49.31; H, 7.13; Found: C, 49.16; H,7.09.

EXAMPLE 2(S)-1-(Benzyloxy)-2-[(diisopropylphosphono)methoxy]-3-iodopropane

A mixture of(R)-3-O-benzyl-2-O-[(diisopropylphosphono)methyl]-1-O-(methanesulfonyl)glycerol(10.0 g, 22.8 mmol) and sodium iodide (5.15 g, 34.4 mmol) in 70 mL ofacetone was heated at reflux for 14 hours. The mixture was concentratedto about 30 mL volume, and insoluble material was removed by filtration.The filtrate was concentrated in vacuo, and the residue was purified byflash chromatography on silica gel (methylene chloride:acetone=1:0 to5:1) to give 9.51 g (89%) of the title compound as an oil.

[α]_(D) ²⁰ : -0.82° (c 2.30, CH₃ OH).

¹ H NMR (CDCl₃, 300 MHz) δ: 7.24-7.35 (m, 5 H, PhH), 4.66-4.80 (m, 2 H,2×POCH), 4.52 (s, 2 H, OCH₂ Ph), 3.88 (dd, J=8.7, 13.6 Hz, 1 H, OCH₂ P),3.82 (dd, J=8.7, 13.6 Hz, 1 H, OCH₂ P), 3.52-3.68 (m, 3 H, CH₂ OBn andH-2), 3.37 (dd, J=3.6, 10.5 Hz, 1 H, CH₂ I), 3.31 (dd, J=6.0, 10.5 Hz, 1H, CH₂ I), and 1.23-1.34 (m, 12 H, 4×POCHCH₃).

¹³ C NMR (CDCl₃, 75 MHz) δ: 137.9, 128.4, 127.8, 127.7, 79.4 (d, 3J=11Hz, C-2), 73.3 (OCH₂ Ph), 71.1 (CH₂ OBn), 71.0 (d, ² J_(c),p =3 Hz,POCH), 64.6 (d, ¹ J_(c),p =168 Hz, C-P), 23.7 (t, J=4 Hz, POCHCH₃), and4.9 (CH₂ I).

MS (isobutane, DCI) m/e: 471 (MH⁺).

EXAMPLE 3(R)-1-O-Benzyl-2-O-[(diisopropylphosphono)methyl]-1,2-propanediol

(S)-1-(Benzyloxy)-2-[(diisopropylphosphono)methoxy]-3-iodopropane (11.1g, 23.5 mmol) was mixed with triethylamine (2.85 g, 28.2 mmol) in 15 mLof methanol. To this solution, 10% palladium on carbon (2.0 g) was addedunder nitrogen atmosphere. The reaction was performed in a Parrapparatus at a hydrogen pressure of 40 psi. After 3 hours, the catalystwas removed by filtration, the filtrate was concentrated, and theresidue was purified by flash chromatography on silica gel (methylenechloride:acetone=1:0 to 5:1) to give 7.91 g (98%) of the title compoundas an oil.

[α]_(D) ²⁰ : -7.28° (c 0.29, CH₃ OH).

¹ H NMR (CDCl₃, 300 MHz) δ: 7.20-7.35 (m, 5 H, PhH), 4.66-4.80 (m, 2 H,2×POCH), 4.52 (s, 2 H, OCH₂ Ph), 3.84 (dd, J=8.8, 13.6 Hz, 1 H, OCH₂ P),3.70-3.84 (m, 2 H, 2-CH and OCH₂ P) 3.50 (dd, J=6.0, 10.2 Hz 1 H, CH₂OBn) 3.41 (dd, J=4.4, 10.2 Hz, 1 H, CH₂ OBn), 1.26-1.35 (m, 12H,4×POCHCH₃), and 1.16 (d, J=6.4 Hz, 3 H, H-3).

¹³ C NMR (CDCl₃, 75 MHz) δ: 138.3, 128.4, 127.7, 76.9 (d, ³ J_(c),p =12Hz, C-2), 74.0 and 73.2 (CH₂ OBn and OCH₂ Ph), 70.8 (d, ² J_(c),p =7 Hz,POCH), 63.9 (d, ¹ J_(c),p =169 Hz, OCH₂ P), 23.7 (q, ³ J_(c),p 4 Hz,POCHCH₃), and 16.5 (C-3).

MS (isobutane, DCI) m/e: 345 (MH⁺).

Anal. Calcd. for C₁₇ H₂₉ O₅ P: C, 59.29; H, 8.49; Found: C, 59.26; H,8.37.

EXAMPLE 4 (R)-2-O-[(Diisopropylphosphono)methyl)]-1,2-propanediol

(R)-1-O-Benzyl-2-O-[(diisopropylphosphono)methyl]-1,2-propanediol (7.75g, 22.5 mmol) was dissolved in a mixture of cyclohexene (30 mL) andmethanol (30 mL). To the solution, 20% palladium hydroxide on carbon(1.5 g) was added. The resulting mixture was heated at reflux for 16hours, and the catalyst was removed by filtration. The filtrate wasconcentrated in vacuo, and the residue containing the title compound wasused in the next reaction without further purification.

¹ H NMR (CDCl₃, 300 MHz) δ: 4.62-4.80 (m, 2 H, 2×POCH), 3.88 (dd, J=8.0,13.9 Hz, 1 H, OCH₂ P), 3.67 (dd, J=9.0 Hz, 1 H, OCH₂ P), 3.52-3.68 (m, 2H, H-2 and CH₂ OH), 3.46 (dd, J=7.2, 12.0 Hz, 1 H, CH₂ OH), 2.19 (d,J=6.0 Hz, 3 H, H-3), and 1.28-1.32 (m, 12 H, 4×POCHCH₃).

¹³ C NMR (CDCl₃, 75 MHz) δ: 79.0 (d, ³ J_(c),p =10 Hz, C-2), 70.8 (d, ²J_(c),p =7 Hz, POCH), 70.6 (d, ² J_(c),p =7 Hz, POCH), 65.3 (C-1), 63.3(d, ¹ J_(c),p =170 Hz, OCH₂ P), 23.4 (d, ³ J_(c),p =4 Hz, POCHCH₃), 23.2(d, ³ J_(c),p =5 Hz, POCHCH₃), and 15.4 (C-3).

EXAMPLE 5(R)-2-O-[(Diisopropylphosphono)methyl]-1-O-methanesulfonyl-1,2-propanediol

(R)-2-O-[(Diisopropylphosphono)methyl)]-1,2-propanediol (used crude fromExample 4, 22.5 mmol) was dissolved in 50 mL of methylene chloride andcooled to 0° C. Methanesulfonyl chloride (3.11 g, 27 mmol) was addedslowly to the solution, and then, triethylamine (2.54 g, 45 mmol) wasadded dropwise. After the addition was complete, the mixture was stirredat 0° C. for 30 minutes and then allowed to warm slowly to roomtemperature. Water (50 mL) and methylene chloride (150 mL) were added tothe solution. The aqueous layer was extracted with methylene chloride(2×50 mL). The combined methylene chloride extracts were washed withbrine and dried over magnesium sulfate. Filtration and concentrationunder reduced pressure gave a residue which was purified by flashchromatography on silica gel (methylene chloride:acetone=10:1 to 5:1) toprovide 6.91 g of the title compound as an oil (92% yield for 2 steps).

[α]_(D) ²⁰ : -7.45°, (c 1.45, CH₃ OH).

¹ H NMR (CDCl₃, 300 MHz) δ: 4.52-4.69 (m, 2 H, 2×POCH), 4.10 (dd, J=3.6,11.1 Hz, 1 H, CH₂ OMs), 4.03 (dd, J=6.1, 11.1 Hz, 1 H, CH₂ OMs),3.65-3.78 (m, 2 H, OCH₂ P and H-2), 3.61 (dd, J=9.3, 13.4 Hz, 1 H, OCH₂P), 2.95 (s, 3 H, CH₃ SO₂), 1.20 (d, J=6.4 Hz, 12 H, 4×POCHCH₃), and1.10 (d, J=6.5 Hz, 3 H, H-3).

¹³ C NMR (CDCl₃, 75 MHz) δ: 75.3 (d, ³ J_(c),p =12 Hz, C-2), 72.0 (CH₂OMs), 71.1 (d, ² J_(c),p =4 Hz, POCH), 71.0 (d, ² J_(c),p =4 Hz, POCH),63.72 (d, ¹ J_(c),p =171 Hz, OCH₂ P), 37.4 (CH₃ SO₂), 23.4 (d, ³ J_(c),p=4 Hz, POCHCH₃), 23.2 (d, ³ J_(c),p =4 Hz, POCHCH₃), and 15.3 (C-3).

EXAMPLE 6(R)-2-Amino-6-chloro-9-[2-[(diisopropylphosphono)methoxy]propyl]purine

(R)-2-O-[(Diisopropylphosphono)methyl]-1-O-methanesulfonyl-1,2-propanediol(2.0 g, 6.02 mmol) was mixed with 2-amino-6-chloropurine (1 23 g, 7.22mmol) and cesium carbonate (3.92 g, 12.0 mmol) in 40 mL of acetonitrile.The mixture was gently refluxed under nitrogen atmosphere for 24 hours,then allowed to cool to room temperature, and filtered. The solvent wasremoved under reduced pressure The residue was purified by flashchromatography on silica gel twice (first time, methylenechloride:acetone=3:1 to 0:1; second time, methylenechloride:methanol=15:1 to 10:1). The title compound (0.85 g, 35% yield)was isolated as a glassy material which was crystallized from ethylacetate-diethyl ether: mp 133°-135° C.

[α]_(D) ²⁰ : -41.56° (c 0.99, CH₂ Cl₂).

¹ H NMR (CDCl₃, 300 MHz) δ: 7.92 (s, 1 H, H-8), 5.06 (br s, 2 H, NH₂),4.58-4.72 (m, 2 H, 2×POCH), 4.20 (dd, J=2.6, 14.3 Hz, 1 H, H-1'), 4.03(dd, J=7.2, 14.3 Hz, 1 H, H-1'), 3.82-3.95 (m, 1 H, H-2'),3.76 (dd,J=9.2, 13.4 Hz, 1 H, OCH₂ P), 3.57 (dd, J=9.8, 13.7 Hz, 1 H, OCH₂ P),1.18-1.31 (m, 15 H, POCHCH₃ and H-3').

¹³ C NMR (CDCl₃) δ: 159.2, 154.2, 151.4, 144.0, 125.1, 75.9 (d, ³J_(c),p =12 Hz, C-2'), 71.2 (d, ² J_(c),p =7 Hz, POCH), 63.5 (d, ¹J_(c),p =170 Hz, OCH₂ P), 47.9 (C-1'), 23.8 (d, J=Hz, POCHCH₃), and 16.3(C-3 ).

MS (FAB) m/e: 406 (MH⁺).

Anal. Calcd. for C₁₅ H₂₅ N₅ O₄ PCl: C, 44.40; H, 6.14; N, 17.26; Found:C, 44.46; H, 6.14; N, 16.99.

EXAMPLE 7 (R)-9-[2-(Phosphonomethoxy)propyl]guanine [(R)-2'-methylPMEG]

(R)-2-Amino-6-chloro-9-[2-[(diisopropylphosphono)methoxy]propyl]purine(0.38 g, 0.93 mmol) was dissolved in 5 mL of acetonitrile and treatedslowly with bromotrimethylsilane (1.42 g, 9.34 mmol) under nitrogenatmosphere. The reaction mixture was allowed to stir at room temperaturefor 14 hours, and the solvent was removed under reduced pressure Theresidue was dried in vacuo and then treated with acetone (10 mL) andwater (2 mL). The resulting mixture was stirred at room temperature for20 hours. The mixture was evaporated. The residue was washed withacetone and water. The resulting solid was heated gently at reflux in 10mL of 2N HCl for 4 hours. The solution was evaporated under reducedpressure, and the residue was crystallized from water-methanol to give0.12 g of the title compound as pale yellow crystals. The mother liquorwas concentrated to provide an additional 20 mg of the title compound(total 48% yield): mp 282°-285° C.

[α]_(D) ²⁰ : -26.74° (c 0.43, H₂ O).

¹ H NMR (DMSO-d₆, 300 MHz) δ: 10.58 (br s, 1 H, NH), 7.74 (s, 1 H, H-8),6.46 (br s, 2 H, NH₂), 4.04 (dd, J=4.4, 14.3 Hz, 1 H, H-1'), 3.95 (dd,J=5.8, 14.3 Hz, 1 H, H-1'), 3.78-3.88 (m, 1 H, H-2'), 3.58 (dd, J=9.3,13.0 Hz, 1 H, OCH₂ P), 3.51 (dd, J=9.9, 13.0 Hz, 1 H, OCH₂ P), and 1.02(d, J=6.3 Hz, 3 H, H-3').

¹³ C NMR (DMSO-d₆, 75 MHz) δ: 157.2, 154.0, 151.8, 138.6, 116.1, 75.4(d, ³ J_(c),p =12 Hz, C-2'), 64.4 (d, ¹ J_(c),p =152 Hz, OCH₂ P), 46.5(C-1'), and 16.8 (C-3').

MS (FAB) m/e: 304 (MH⁺).

UV (H₂ O) λ_(max) : 252 nm (ε=12,300).

IR (KBr): 3700-2100 (NH and OH), 1710 (C=O), 1684, 1604 (C=C, C=N), 1104(C-O), 1046, 994, and 952 (P-O) cm⁻¹.

Anal. Calcd. for C₉ H₁₄ N₅ O₅ P.1.25 H₂ O: C, 33.18; H, 5.10; N, 21.50;Found: C, 33.18; H, 4.96; N, 21.58.

EXAMPLE 8(R)-1-(Benzyloxy)-2-[(diisopropylphosphono)methoxy]-3-iodopropane

Sodium iodide (41.6 g, 277 mmol) was added in one portion to a solutionof(R)-1-(benzyloxy)-2-[(diisopropylphosphono)methoxy]-3-(methanesulfonyloxy)propane(prepared according to the procedure described by J. J. Bronson, et al.,in J. Med. Chem., 1989, 32, 1457) (12.1 g, 27.7 mmol) in 100 mL ofacetone. The reaction mixture was heated at reflux for 6 hours and thenallowed to cool to room temperature. The mixture was concentrated invacuo and partitioned between ethyl acetate (200 mL) and water (200 mL).The organic layer was washed with saturated sodium chloride solution,dried over sodium sulfate, filtered, and concentrated in vacuo to afford12.9 g of an orange oil. Purification by column chromatography on silicagel (10:1, 75% ethyl acetate/hexane) gave 12.4 g (95%) of the titlecompound as a clear, colorless liquid.

[α]_(D) ²⁰ : +0.62°, (c 1.1, CH₃ OH).

¹ H NMR (CDCl₃, 300 MHz) δ: 7.26-7.43 (m, 5 H, PhH), 4.67-4.79 (m, 2 H,2×POCH), 4.52 (s, 2 H, OCH₂ Ph), 3.79-3.92 (m, 2 H, OCH₂ P), 3.53-3.67(m, 3 H, H-2 and CH₂ OBn) 3.29-3.39 (m, 2 H, CH₂ I), and 1.29-1.33 (m,12 H, 4×POCHCH₃).

MS (methane, DCI) m/e: 471 (MH⁺).

EXAMPLE 9(S)-1-O-Benzyl-2-O-[(diisopropylphosphono)methyl]-1,2-propanediol

A solution of(R)-1-(benzyloxy)-2-[(diisopropylphosphono)methoxy]-3-iodopropane (12.0g, 25.5 mmol) in 15 mL of methanol was treated with triethylamine (3.10g, 30.6 mmol) and 10% palladium on carbon (2.0 g), and the mixture wasplaced under 40 psi hydrogen atmosphere in a Parr shaker apparatus.After 2 hours, the reaction mixture was filtered through a 1" pad ofCelite, and the collected solid was washed with methanol. The filtratewas concentrated and treated with ethyl acetate (200 mL). Theprecipitate was removed by filtration, the filtrate was concentrated invacuo, and the residue was purified by column chromatography on silicagel (10:1, 75% ethyl acetate/hexane) to afford 8.24 g (94%) of the titlecompound as a clear, colorless oil.

[α]_(D) ²⁰ : 5.67°, (c 0.97, CH₃ OH).

¹ H NMR (CDCl₃, 300 MHz) δ: 7.22-7.34 (m, 5 H, PhH), 4.66-4.78 (m, 2 H,2×POCH), 4.51 (s, 2 H, OCH₂ Ph), 3.70-3.89 (m, 3 H, OCH₂ P and H-2),3.39-3.53 (m, 2 H, CH₂ OBn), 1.27-1.31 (m, 12 H, 4×POCHCH₃), and 1.16(d, J=6 Hz, 3 H, H-3).

MS (methane, DCI) m/e: 345 (MH⁺)

EXAMPLE 10 (S)-2-O-[(Diisopropylphosphono)methyl]-1,2-propanediol

A solution of(S)-1-O-benzyl-2-O-[(diisopropylphosphono)methyl]-1,2-propanediol (8.20g, 23.8 mmol) in 1:1 ethanol/cyclohexene (80 mL) was treated with 20%palladium hydroxide on carbon (4.0 g), and the mixture was heated atreflux for 18 hours. The reaction mixture was then filtered through a 1"pad of Celite, and the filtrate was concentrated in vacuo to give 6.3 gof the title compound as a clear, colorless oil which was used in thefollowing reaction without purification.

¹ H NMR (CDCl₃, 300 MHz) δ: 4.66-4.81 (m, 2 H, 2×POCH), 3.89 (dd, J=8,14 Hz, 1 H, OCHP), 3.55-3.81 (m, 3 H, OCHP, H-2, and CHOH), 3.46 (dd,J=7, 12 Hz, 1 H, CHOH), 3.10 (br s, 1 H, OH), 1.25-1.32 (m, 12 H,4×POCHCH₃), and 1.10 (d, J=6 Hz, 3 H, H-3).

MS (methane, DCI) m/e: 255 (MH⁺).

EXAMPLE 11(S)-2-O-[(Diisopropylphosphono)methyl]-1-O-methanesulfonyl-1,2-propanediol

Methanesulfonyl chloride (3.27 g, 28.5 mmol) was added in 1 portion toan ice-cold solution of(S)-2-O-[(diisopropylphosphono)methyl]-1,2-propanediol (used crude fromExample 10, 23.8 mmol) in methylene chloride (100 mL). Triethylamine(3.61 g, 35.7 mmol) was added dropwise via syringe over 5 minutes. Theresulting pale-yellow slurry was allowed to warm to room temperature andstirred further for 14 hours. The reaction mixture was poured into water(100 mL), the layers were separated, and the aqueous layer was extractedwith methylene chloride (100 mL). The combined organic layers werewashed with aqueous sodium bicarbonate solution (75 mL) and saturatedsodium chloride solution (75 mL), dried over magnesium chloride,filtered, and concentrated in vacuo to afford 8.3 g of an orange oil.Purification by column chromatography on silica gel (10 1, 75% ethylacetate/hexane to ethyl acetate) gave 6.49 g (82%) of the title compoundas a pale-yellow oil.

[α]_(D) ²⁰ : +9.62°, (c 0.69, CH₃ OH).

¹ H NMR (CDCl₃, 300 MHz) δ: 4.65-4.80 (m, 2 H, 2×POCH), 4.21 (dd, J=4,11 Hz, 1 H, CH₂ OMs), 4.14 (dd, J=6, 11 Hz, 1 H, CH₂ OMs), 3.68-3.88 (m,3 H, OCH₂ P and H-2), 3.06 (s, 3 H, CH₃ SO₂), 1.30 (d, J=6 Hz, 12 H,4×POCHCH₃), and 1.21 (d, J=6 Hz, 3 H, H-3).

MS (methane, DCI) m/e: 333 (MH⁺).

EXAMPLE 12(S)-2-Amino-6-chloro-9-[2-[(diisopropylphosphono)methoxy]propyl]purine

2-Amino-6-chloropurine (1.40 g, 8.3 mmol) was added portionwise to aslurry of sodium hydride (0.25 g, 80% dispersion in oil, 8.3 mmol) indimethylformamide (50 mL) at room temperature. Vigorous bubbling wasnoted during the addition. After 30 minutes, the clear, yellow solutionwas treated with a solution of(S)-2-O-[(diisopropylphosphono)methyl]-1-O-methanesulfonyl-1,2-propanediol(2.50 g, 7.5 mmol) in dimethylformamide (5 mL), and the reaction mixturewas heated to 100° C. After 5 hours, the mixture was allowed to cool toroom temperature and concentrated in vacuo. The residue was purified bycolumn chromatography on silica gel (20:1, 2% to 4% to 8%methanol/methylene chloride) to provide 1.89 g (62%) of the titlecompound as a viscous pale yellow oil.

[α]_(D) ²⁰ : +48.16°, (c 1.1, CH₃ OH).

¹ H NMR (DMSO-d₆, 300 MHz) δ: 8.01 (s, 1 H, H-8), 6.88 (br s, 2 H, NH₂),4.38-4.52 (m, 2 H, 2×POCH), 3.89-4.16 (m, 3 H, H-1' and H-2'), 3.77 (dd,J=9, 14 Hz, 1 H, OCH₂ P), 3.64 (dd, J=10, 14 Hz, 1 H, OCH₂ P), and1.08-1.18 (m, 15 H, 4×POCHCH₃ and H-3').

¹³ C NMR (DMSO-d₆, 75 MHz) δ: 159.8, 154.7, 151.8, 144.2 (C-8), 125.5(C-5), 76.3 (d, ³ J_(c),p =12 Hz, C-2'), 71.6 (d, 2J=7 Hz, POCH), 63.9(d, ¹ J_(c),p =170 Hz, OCH₂ P), 48.3 (C-1'), 24.02 (d, ³ J_(c),p =7 Hz,POCHCH₃), 24.1 (d, ³ J_(c),p =7 Hz, POCHCH₃), and 16.7 (C-3').

MS (methane, DCI) m/e: 406 (MH⁺).

UV (CH₃ OH)λ_(max) : 310 nm (ε=7,800), 248 nm (ε=4,700).

EXAMPLE 13 (S)-9-[2-(Phosphonomethoxy)propyl]guanine [(S)-2'-methylPMEG]A. (S)-2-Amino-6-bromo-9-[2-(phosohonomethoxy)propyl]purine

A mixture of(S)-2-amino-6-chloro-9-[2-[(diisopropylphosphono)methoxy]propyl]purine(1.80 g, 4.40 mmol) in acetonitrile (15 mL) at room temperature wastreated dropwise via syringe with bromotrimethylsilane (6.79 g, 44.3mmol). The yellow solution was stirred for 16 hours and thenconcentrated in vacuo. The residue was coevaporated with acetonitrile(2×25 mL), placed under high vacuum for 4 hours, and then treated withwater (20 mL) and acetone (100 mL). The resulting slurry was filteredand the collected material washed with acetone and diethyl ether toafford 1.30 g (81%) of the title compound as a pale-yellow solid.

¹ H NMR (DMSO-d₆, 300 MHz) δ: 8.09 (s, 1 H, H-8), 6.91 (br s, 2 H, NH₂),4.14 (dd, J=4, 14 Hz, 1 H, H-1'), 4.02 (dd, J=6, 14 Hz, 1 H, H-1'),3.83-3.93 (m, 1 H, H-2'), 3.47-3.63 (m, 2 H, OCH₂ P), and 1.03 (d, J=6Hz, 3 H, H-3').

MS (methane, DCI) m/e: 366 (MH⁺).

UV (CH₃ OH)λ_(max) : 312 nm (ε=7,000), 248 nm (ε=3,400).

B. (S)-9-[2-(Phosphonomethoxy)propyl]guanine

A slurry of (S)-2-amino-6-bromo-9-[2-(phosphonomethoxy)propyl]purine(1.20 g, 3.20 mmol) [from Step A] in 10% aqueous HCl solution (25 mL)was heated at reflux for 5 hours. The resulting clear, pale yellowsolution was allowed to cool to room temperature and concentrated invacuo. The residue was coevaporated with water (3×25 mL), dissolved inwater to a volume of 5 mL, and treated with ethanol (100 mL). Theresulting slurry was filtered, and the collected solid was dissolved inwater and lyophilized to provide 0.66 g (66%) of the title compound as awhite solid: mp 270°-272° C.

[α]_(D) ²⁰ : +34.66°, (c=0.68, H₂ O).

¹ H NMR (DMSO-d₆, 300 MHz) δ: 10.75 (s, 1 H, NH), 7.74 (s, 1 H, H-8),6.45 (br s, 2 H, NH₂), 5.67 (br s, OH and H₂ O), 4.01 (dd, J=4,14 Hz, 1H, H-1'), 3.91 (dd. J=6,14 Hz, 1 H, H-1'), 3.77-3.82 (m, 1 H, H-2'),3.44-3.58 (m, 2 H, OCH₂ P), and 0.98 (d, J=6 Hz, 3 H, H-3').

¹³ C NMR (DMSO-d₆, 75 MHz) δ: 157.1, 154.1, 151.9, 138.6 (C-8), 115.8(C-5), 75.3 (d, ³ J_(c),p =12 Hz, C-2'), 64.5 (d, ¹ J_(c),p =165 Hz,OCH₂ P), 46.6 (C-1'), and 16.9 (C-3').

MS (methane, DCI) m/e: 304 (MH⁺).

UV (H₂ O)λ_(max) : 252 nm (ε=11,000), 278 nm (ε=8,000); (0.1NNaOH)λ_(max) : 268 nm (ε=9,600); (0.1N HCl)λ_(max) : 254 nm (ε=10,600),278 nm (ε=6,900).

Anal. Calcd for C₉ H₁₄ N₅ O₅ P.1.66 H₂ O: C, 32.45; H, 5.19; N, 21.03;Found: C, 32.45; H, 4.73; N, 20.93.

EXAMPLE 14(R)-6-O-Benzyl-9-[3-(benzyloxy)-2-[(diisopropylphosphono)methoxy]propyl]guanine

(R)-3-O-Benzyl-2-O-[(diisopropylphosphono)methyl]-1-O-(methanesulfonyl)glycerol(13.8 g, 31.5 mmol), 6-O-benzylguanine (9.07 g, 37.8 mmol), and cesiumcarbonate (12.3 g, 37.76 mmol) were mixed in 150 mL of dry acetonitrileunder nitrogen atmosphere. The mixture was heated gently at reflux for16 hours. The solvent was removed under reduced pressure, and then,methylene chloride (150 mL) was added to the residue. Insoluble materialwas removed by filtration, and the filtrate was concentrated underreduced pressure to give a residue which was purified by flashchromatography on silica gel (first time, methylenechloride:methanol=30:1 to 10:1; second time, methylenechloride:acetone=2:1 to 0:1) to provide 10.86 g (59% yield) of the titlecompound as a thick mass. The product crystallized upon standing at roomtemperature. The solid was triturated with diethyl ether to give thetitle compound as white crystals: mp 75°-79° C.

[α]_(D) ²⁰ : +16.7° (c 1.02, CH₂ Cl₂).

¹ H NMR (CDCl₃, 300 MHz) δ: 7.67 (s, 1 H, H-8), 7.45-7.52 and 7.20-7.35(2 m, 10 H, ArH), 5.54 (s, 2 H, 6-OCH₂ Ph), 4.84 (br s, 2 H, NH₂),4.59-4.71 (m, 2 H, 2×POCH), 4.50 (s, 2 H, 3'-OCH₂ Ph), 4.30 (dd, J=4.1,14.4 Hz, 1 H, H-1'), 4.17 (dd, J=6.5, 14.4 Hz, 1 H, H-1'), 3.90-3.98 (m,1H, H-2'), 3.83 (dd, J=8.7, 13.6 Hz, 1 H, OCH₂ P), 3.75 (dd, J=8.0, 13.6Hz, 1 H, OCH₂ P), 3.50 (d, J=5.0 Hz, 2 H, CH₂ OBn), and 1.16-1.32 (m, 12H, 4×POCHCH₃).

¹³ C NMR (CDCl₃, 75 MHz) δ: 161.2, 159.5, 154.5, 140.7, 137.7, 136.7,128.6, 128.4, 128.3, 128.0, 127.9, 115.1, 78.8 (d, ³ J_(c),p =11 Hz,C-2'), 73.5 (3'-OCH₂ Ph), 71.1 (d, ² J_(c),p =5 Hz, POCH), 71.0 (d, ¹J_(c),p =7 Hz, POCH), 68.8 and 67.8 (C-3' and 6-O-CH₂ Ph), 64.9 (d, ¹J_(c),p =168 OCH₂ P), 43.9 (C-1'), 23.8 (d, ³ J_(c),p =4 Hz, POCHCH₃),and 23.7 (d, ³ J_(c),p =4 Hz, POCHCH₃).

MS (FAB) m/e: 584 (MH⁺).

Anal. Calcd. for C₂₉ H₃₈ N₅ O₆ P: C, 59.68; H, 6.56; N, 11.99; Found: C,59.29; H, 6.48; N, 12.09.

EXAMPLE 15(R)-9-[2-[(Diisopropylphosphono)methoxy]-3-hydroxypropyl]guanine

A solution of6-O-benzyl-9-[3-(benzyloxy)-2-[(diisopropylphosphono)methoxy]propyl]guanine(4.00 g, 5.85 mmol) in ethanol and cyclohexene (30 mL of each) wastreated with 20% palladium hydroxide on carbon (1.0 g). The mixture washeated gently at reflux for 3 days. The catalyst was collected byfiltration, boiled in methanol (100 mL) for 2 minutes, and the resultingslurry was filtered. The process was repeated 3 times. The combinedfiltrates were concentrated under reduced pressure, and the residue waspurified by flash chromatography on silica gel (methylenechloride:methanol=10:1 to 5:1). The crude product was recrystallizedfrom methanol-ethyl acetate to give 2.16 g (92% yield) of the titlecompound as a crystalline solid.

[α]_(D) ²⁰ : +23.7° (c 1.95, CH₃ OH).

¹ H NMR (CD₃ OD, 300 MHz) δ: 7.49 (s, 1 H, H-8), 4.65 (s, 2 H, NH₂),4.34-4.46 (m, 2 H, 2×POCH), 4.05 (dd, J=4.0, 14.5 Hz, 1 H, H-1'), 3.95(dd, J=6.6, 14.5 Hz, 1 H, H-1'), 3.71 (dd, J=8.9, 13.8 Hz, 1 H, OCH₂ P),3.63 (dd, J=9.5, 13.8 Hz, 1 H, OCH₂ P), 3.58-3.66 (m, 1 H, H-2'), 3.39(dd, J=5.0, 12.2 Hz, 1 H, H-3'), 3.33 (dd, J=5.0, 12.2 Hz, 1 H, H-3'),and 1.00-1.10 (m, 12 H, 4×POCHCH₃).

¹³ C NMR (CD₃ OD, 75 MHz) δ: 159.8, 155.7, 153.7, 140.9, 117.4, 81.9 (d,³ J_(c),p =12 Hz, C-2'), 73.3 (d, ² J_(c),p =6 Hz, POCH), 65.0 (d, ¹J_(c),p =169 Hz, OCH₂ P), 61.5 (C-3'), 44.6 (C-1'), and 24.1 (d, ³J_(c),p =4 Hz, POCHC₃).

A sample of the solid product was recrystallized from water to givecrystals of the title compound

Anal. Calcd. for C₁₅ H₂₆ N₅ O₆ P.0.25 H₂ O: C, 44.28; H, 6.56; N, 17.21;Found: C, 44.23; H, 6.44; N, 17.36.

EXAMPLE 16 (R)-9-[3-Hydroxy-2-(phosphonomethoxy)propyl]guanine[(R)-HPMPG]

A solution of(R)9-[2-[(diisopropylphosphono)methoxy]3-hydroxypropyl]guanine (0.20 g,0.50 mmol) in 5 mL of dry acetonitrile was treated withtrimethylsilylbromide (0.99 g, 6.45 mmol) under nitrogen atmosphere. Theresulting solution was protected from light and stirred at roomtemperature for 14 hours. The solvent was removed under reducedpressure, and the residue was dried under vacuum. To the residue, water(1 mL) and acetone (4 mL) were added. The mixture was stirred at roomtemperature overnight and then the solvent removed. The residue wastriturated with methylene chloride and filtered. The collected solid wasrecrystallized from water-methanol to give 127 mg (80% yield) of thetitle compound as white crystals: mp 249° C. (dec.).

[α]_(D) ²⁰ : +32.3°, (c 1.11, H₂ O).

¹ H NMR (DMSO-d₆, 300 MHz) δ: 7.73 (s, 1 H, H-8), 6.49 (br s, 2 H, NH₂),4.17 (dd, J=4.1, 14.3 Hz, 1 H, H-1'), 3.98 (dd, J=6.6, 14.3 Hz, 1 H,H-1'), 3.61-3.73 (m, 1 H, H-2'), 3.64 (dd, J=8.9, 13.3 Hz, 1 H, OCH₂ P),3.58 (dd, J=9.3, 13.3 Hz, 1 H, OCH₂ P), and 3.32-3.45 (m, 2 H, H-3').

¹³ C NMR (DMSO-d₆, 75 MHz) δ: 157.1, 154.1, 151.6, 138.6, 115.9, 80.5(d, ³ J_(c),p =10 Hz, C-2'), 65.6 (d, ¹ J_(c),p =161 Hz, OCH₂ P), 60.2(C-3'), and 43.2 (C-1').

Anal. Calcd. for C₉ H₁₄ N₅ O₆ P: C, 33.48; H, 4.23; N, 21.59; Found: C,33.86; H, 4.42; N, 21.93.

EXAMPLE 17(S)-6-O-Benzyl-9-[3-(benzyloxy)-2-[(diethylphosphono)methoxy]propyl]guanine

Following the general procedure described in Example 14 and utilizing(S)-3-O-benzyl-2-O-[(diethylphosphono)methyl]-1-O-(methanesulfonyl)glycerol as the starting material, there was thereby produced the titlecompound.

[α]_(D) ²⁰ : -24.05°, (c 1.2, CH₃ OH).

¹ H NMR (CDCl₃, 300 MHz) δ: 7.64 (s, 1 H, H-8), 7.23-7.49 (m, 10 H,2×PhH), 5.52 (s, 2 H, 6-O-CH₂ Ph), 4.87 Hz, 1 H, H-1'), 3.73-4.17 (m, 8H, H-1', H-2', OCH₂ P, and 2×POCH₂), 3.49-3.53 (m, 2H, CH₂ OBn), 1.25(t, J=6 Hz, 3 H, POCH₂ CH₃), and 1.20 (t, J=6 Hz, 3 H, POCH₂ CH₃).

¹³ C NMR (CDCl₃, 75 MHz) δ: 161.7, 159.9, 155.0, 141.2 (C-8), 138.2,137.1, 129.1, 128.9, 128.9, 128.8, 128.5, 128.4, 115.8 (C-5), 79.4 (d, ³J_(c),p =12 Hz, C-2'), 74.0 (OCH₂ Ph), 69.3 and 68.3 (OCH₂ Ph and C-3'),64.6 (d, ¹ J_(c),p =165 Hz, OCH₂ P), 62.8 (d, ² J_(c),p =6 Hz, POCH₂),62.7 (d, ² J_(c),p =6 Hz, POCH₂), 44.4 (C-1'), and 16.6 (d, ³ J_(c),p =6Hz, POCH₂ CH₃).

MS (methane, DCI) m/e: 556 (MH⁺).

UV (CH₃₀ H)λ_(max) : 284 nm (ε=11,100).

EXAMPLE 18 (S)-9-[3-Hydroxy-2-[(diethylphosphono)methoxy]propyl]guanine

Following the general procedure described in Example 15 and utilizingthe compound of Example 17 as the starting material, there was therebyproduced the title compound.

[α]_(D) ²⁰ : -29.54° (c 1.3, CH₃ OH).

¹ H NMR (DMSO-d₆, 300 MHz) δ: 10.55 (s, 1 H, NH), 7.60 (s, 1 H, H-8),6.45 (s, 2 H, NH₂), 4.92 (t, J=5 Hz, 1 H, exch, OH), 4.11 (dd, J=4, 15Hz, 1 H, H-1'), 3.73-4.02 (m, H, H-1', H-2', OCH₂ P, and 2×POCH₂), 3.44(apparent t, J=5 Hz, 2 H, H-3'), 1.17 (t, J=6 Hz, 3 H, POCH₂ CH₃), and1.14 (t, J=6 Hz, 3 H, POCH₂ CH₃).

¹³ C NMR (DMSO-d₆) δ: 157.4, 154.0, 151.9, 138.5 (C-8), 116.5 (C-5),80.5 (d, ³ J_(c),p =12 Hz, C-2'), 63.0 (d, ¹ J_(c),p =150 Hz, OCH₂ P),62.0 (d, ² J_(c),p =6 Hz, POCH₂), 61.8 (d, ² J_(c),p =6 Hz, POCH₂), 60.1(C-3'), 43.4 (C-1'), and 16.2 (d, ³ J_(c),p =6 Hz, POCH₂ CH₃).

MS (FAB) m/e: 376 (MH⁺).

UV (CH₃ OH)λ_(max) : 254 nm (ε=12,700).

Anal Calcd for C₁₃ H₂₂ N₅ O₆ P.0.75 H₂ O: C, 40.16; H, 6.09; N, 18.01;Found: C, 40.21; H, 5.71; N, 17.82.

EXAMPLE 19 (S)-9-[3-Hydroxy-2-(phosphonomethoxy)propyl]guanine[(S)-HPMPG]

Following the general procedure described in Example 16 and utilizingthe compound of Example 18 as the starting material, there was therebyproduced the title compound.

[α]_(D) ²⁰ : -35.83° (c 0.49, H₂ O).

¹ H NMR (DMSO-d₆, 300 MHz) δ: 11.10 (s, 1 H, NH), 8.46 (s, 1 H, H-8),6.85 (s, 2 H, NH₂), 4.25 (dd, J=3, 14 Hz, 1 H, H-1'), 4.04 (dd, J=8, 14Hz, 1 H, H-1'), and 3.23-3.74 (m, 5 H, H-2', OCH₂ P, and 2×H-3').

¹³ C NMR (DMSO-d₆, 75 MHz) δ: 154.9, 154.7, 150.5, 138.1 (C-8), 110.9(C-5), 79.7 (d, ³ J_(c),p =12 Hz, C-2'), 65.3 (d, ¹ J_(c),p =160 Hz,OCH₂ P), 60.1 (C-3'), and 44.5 (C-1').

MS (FAB) m/e: 320 (MH⁺).

UV (H₂ O)λ_(max) : 252 nm (ε=10,000).

Anal. Calcd for C₉ H₁₄ N₅ O₆ P: C, 33.86; H, 4.42; N, 21.94; Found: C,33.59; H, 4.34; N, 21.72.

EXAMPLE 20 (R)-1,2-Propanediol

The title compound can be prepared from (R)-lactic acid using aprocedure similar to that of C. Melchiorre (Chem. Ind., 1976, 218).

[α]_(D) ²⁰ : -17.3° (neat).

EXAMPLE 21 (R)-1-O-[p-(Methoxyphenyl)diphenylmethyl]-1,2-propanediol

Triethylamine (234 g, 2.31 mol) and 4-dimethylaminopyridine (1 g, 8mmol) were added to (R)-1,2-propanediol (80 g, 1.05 mol) in a mixture ofethyl acetate and methylene chloride (2:1, 0.8 L) under a nitrogenatmosphere. To this mixture, p-anisylchlorodiphenylmethane (356.5 g,1.16 mol) was added at 0° C. The reaction mixture was stirred at 0° C.for 30 minutes and then at room temperature for 15 hours. The solid wasremoved by filtration. The filtrate was stripped of solvent, and theresidue was put on a silica gel column (500 g) and eluted with a mixtureof ethyl collected (366.6 g) was dried under vacuum and used withoutfurther purification.

¹ H NMR (300 MHz, CDCl₃) δ: 7.45-7.15 (m, 12 H, ArH), 6.83-6.80 (M, 2 H,ArH), 4.00-3.90 (m, 1 H, H-2), 3.77 (s, 3 H, OCH₃), 3.10 (dd, J=3.4, 9.2Hz, 1 H, H-1), 2.95 (dd, J=7.9, 9.2 Hz, 1 H, H-1), 2.35 (br d, 1 H, OH),1.07 (d, J=6.4 Hz, 3 H, H-3).

¹³ C NMR (300 MHz, CDCl₃) δ: 158.8, 144.6, 135.7, 130.5, 128.0, 127.7,127.1, 113.2, 86.3, 68.8 (1-C), 67.0 (2-C), 55.1 (OCH₃), 18.7 (3-C).

EXAMPLE 22 (R)-2-O-[(Diisopropylphosphono)methyl)]-1,2-propanediol

Sodium hydride (80% in mineral oil, 24 g, 0.80 mol) was added in fiveportions to a solution of the crude(R)-1-O-[p-(methoxyphenyl)diphenylmethyl]-1,2-propanediol (232 g, 0.66mol) of Example 21 in 1 L of anhydrous tetrahydrofuran at 0° C. under anitrogen atmosphere. The mixture was stirred at 0° C. for 30 minutes andthen heated at reflux for 5 hours. The resulting reaction mixture wascooled to 0° C., and a solution of tosyloxymethyl diisopropylphosphonate(280 g, 0.80 mol) in 300 mL of anhydrous tetrahydrofuran was added via acannula. The mixture was stirred in ice-bath and slowly warmed to roomtemperature overnight (18 hours). The resulting brown slurry wasfiltered through a pad of Celite and washed with methylene chloride.After the solvent was removed, the residue was filtered through a silicagel column and eluted with mixtures of ethyl acetate and hexane (1:5 to1:0) to give a crude product of (R)-2-O-[(diisopropylphosphono)methyl)]-1-O-[p-(methoxyphenyl)-diphenylmethyl]-1,2-propanediolas an oil.

¹ H NMR (300 MHz, CDCl₃) δ: 7.44 (d, J=7.0 Hz, 3 H, ArH), 7.33-7.16 (m,9 H, ArH), 6.81 (d, J=8.1 Hz, ArH), 4.80-4.56 (m, 2 H, 2×POCH), 3.86(dd, J=9.1, 13.6 Hz, OCH₂ P), 3.76 and 3.88-3.76 (s over m, 4 H, OCH₃and OCH₂ P), 3.77-3.68 (m, 1 H, H-2), 3.16 (dd, J=5.9, 9.6 Hz, 1 H,H-1), 3.01 (dd, J=4.1, 9.6 Hz, 1 H, H-1), 1.32-1.27 (m, 12 H, POCHCH₃),1.14 (d, J=6.1 Hz, 3 H, H-3).

¹³ C NMR (300 MHz, CDCl₃) δ: 158.6, 144.6, 135.7, 130.4, 128.5, 127.8,126.8, 113.0, 86.2, 77.4, (d, ³ J_(c),p =12 Hz, C-2), 70.7 (t, ² J_(c),p=6 Hz, POCH), 67.0 (1-C), 64.1 (d, ¹ J_(c),p =169 Hz, OCH₂ P), 54.9(OCH₃), 23.8 (d, ³ J_(c),p =3 Hz, POCHCH₃), 23.7 (d, ³ J_(c),p =3 Hz,POCHCH₃), 16.8 (3-C).

10-Camphorsulphonic acid (21 g) was added to a solution of the crude(R)-2-O-[(diisopropylphosphono)methyl)]-1-O-[p-(methoxyphenyl)diphenylmethyl]-1,2-propanediolin 1.8 L of methanol. The solution was heated at reflux for 7 hours.After the solvent was evaporated, the residue was purified by columnchromatography on silica gel (first time, ethyl acetate:hexane=1:2 to1:0 and then ethyl acetate:ethanol=10:1; second time, methylenechloride:acetone=5:1 to 0:1) to give 40.8 g (24% yield) of the titlecompound as an oil which is identical to the compound of Example 4.

What is claimed is:
 1. A method for treating a patient infected with aretrovirus, which comprises administering to said patient atherapeutically anti-retroviral effective amount of a composition freeof (S)-9-[2-(phosphonomethoxy)propyl]-guanine which compositioncomprises (R)-9-[2-(phosphonomethoxy)propyl]-guanine or apharmaceutically acceptable salt or solvate thereof, either alone or ina mixture with a pharmaceutically acceptable carrier.
 2. A method fortreating human cells infected with a retrovirus, which comprisesadministering to said cells a therapeutically anti-retroviral effectiveamount of a composition free of(S)-9-[2-(phosphonomethoxy)propyl]-guanine which composition comprises(R)-9-[2-(phosphonomethoxy)propyl]-guanine or a pharmaceuticallyacceptable salt or solvate thereof, either alone or in a mixture with apharmaceutically acceptable carrier.